scholarly journals Changes in foraminal area with anterior decompression versus keyhole foraminotomy in the cervical spine: a biomechanical investigation

2017 ◽  
Vol 27 (6) ◽  
pp. 620-626 ◽  
Author(s):  
Jacqueline Nguyen ◽  
Bryant Chu ◽  
Calvin C. Kuo ◽  
Jeremi M. Leasure ◽  
Christopher Ames ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Cervical Disc ◽  
Cross Sectional ◽  
Key Points ◽  
Biomechanical Investigation ◽  
Flexion Extension ◽  
Indirect Decompression ◽  
Pure Moment ◽  
Keyhole Foraminotomy ◽  
Foraminal Area

OBJECTIVEAnterior cervical discectomy and fusion (ACDF) with or without partial uncovertebral joint resection (UVR) and posterior keyhole foraminotomy are established operative procedures to treat cervical disc degeneration and radiculopathy. Studies have demonstrated reliable results with each procedure, but none have compared the change in neuroforaminal area between indirect and direct decompression techniques. The purpose of this study was to determine which cervical decompression method most consistently increases neuroforaminal area and how that area is affected by neck position.METHODSEight human cervical functional spinal units (4 each of C5–6 and C6–7) underwent sequential decompression. Each level received the following surgical treatment: bilateral foraminotomy, ACDF, ACDF + partial UVR, and foraminotomy + ACDF. Multidirectional pure moment flexibility testing combined with 3D C-arm imaging was performed after each procedure to measure the minimum cross-sectional area of each foramen in 3 different neck positions: neutral, flexion, and extension.RESULTSNeuroforaminal area increased significantly with foraminotomy versus intact in all positions. These area measurements did not change in the ACDF group through flexion-extension. A significant decrease in area was observed for ACDF in extension (40 mm2) versus neutral (55 mm2). Foraminotomy + ACDF did not significantly increase area compared with foraminotomy in any position. The UVR procedure did not produce any changes in area through flexion-extension.CONCLUSIONSAll procedures increased neuroforaminal area. Foraminotomy and foraminotomy + ACDF produced the greatest increase in area and also maintained the area in extension more than anterior-only procedures. The UVR procedure did not significantly alter the area compared with ACDF alone. With a stable cervical spine, foraminotomy may be preferable to directly decompress the neuroforamen; however, ACDF continues to play an important role for indirect decompression and decompression of more centrally located herniated discs. These findings pertain to bony stenosis of the neuroforamen and may not apply to soft disc herniation. The key points of this study are as follows. Both ACDF and foraminotomy increase the foraminal space. Foraminotomy was most successful in maintaining these increases during neck motion. Partial UVR was not a significant improvement over ACDF alone. Foraminotomy may be more efficient at decompressing the neuroforamen. Results should be taken into consideration only with stable spines.

Radiography and biomechanics of sixth and seventh cervical vertebrae segments after disc fenestration and after insertion of an intervertebral body spacer

2014 ◽  
Vol 27 (01) ◽  
pp. 54-61 ◽  
Author(s):  
L. Desquilbet ◽  
D. Fitzpatrick ◽  
F. Bernard ◽  
P. Moissonnier
Keyword(s):  
Intervertebral Disc ◽  
Cervical Vertebrae ◽  
Cross Sectional Area ◽  
Cervical Disc ◽  
Sectional Area ◽  
Lateral Bending ◽  
Disc Space ◽  
Cross Sectional ◽  
Radiographic Measurements ◽  
Flexion Extension

SummaryObjectives: To study the radiographic characteristics and the biomechanical properties of the sixth and seventh cervical (C6–C7) vertebral motion unit (VMU) with an intact disc, after disc fenestration, and after placement of an intervertebral body spacer (IVBS).Methods: Six cadaveric C6-C7 VMU were retrieved from six Greyhound cadavers. Each VMU was loaded at 3 Nm of torque sequentially in flexion, extension, and in right and left lateral bending. The range-of-motion (ROM) was measured with a Zebris 3D® system. The intervertebral disc cross-sectional area was measured on lateral and ventrodorsal radiographs. Biomechanical testing and radiographic measurements were performed with an intact disc, after disc fenestration, and after IVBS placement. Data were reported as mean ± SD.Results: The intervertebral disc cross-sectional area was significantly decreased after disc fenestration and increased after IVBS placement, but remained significantly smaller than the area of intact disc in some of the tested conditions. The ROM with an intact disc, after disc fenestration and after IVBS placement, in flexion were 11.5° ± 1.0, 15.2° ± 2.3, and 10.9° ± 4.7, respectively, and in extension were 15.6° ± 3.7, 24.7° ± 6.2, 21.9° ± 4.0, respectively. There was a significant increase in extension ROM after disc fenestration. Intervertebral body spacer placement significantly decreased ROM in flexion but ROM in extension was not different from disc fenestration. No significant changes in lateral bending ROM were detected.Clinical significance: The use of an IVBS reduced disc space collapse but did not restore stability of the VMU to normal values in extension after cervical disc fenestration.

scholarly journals Ranges of Cervical Intervertebral Disc Deformation During an In Vivo Dynamic Flexion–Extension of the Neck

2017 ◽  
Vol 139 (6) ◽  
Author(s):  
Yan Yu ◽  
Haiqing Mao ◽  
Jing-Sheng Li ◽  
Tsung-Yuan Tsai ◽  
Liming Cheng ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Imaging System ◽  
Human Subjects ◽  
Three Dimensional ◽  
Cervical Disc ◽  
Significant Difference ◽  
Flexion Extension ◽  
Fluoroscopic Imaging ◽  
Magnetic Resonance Imaging Mri

While abnormal loading is widely believed to cause cervical spine disc diseases, in vivo cervical disc deformation during dynamic neck motion has not been well delineated. This study investigated the range of cervical disc deformation during an in vivo functional flexion–extension of the neck. Ten asymptomatic human subjects were tested using a combined dual fluoroscopic imaging system (DFIS) and magnetic resonance imaging (MRI)-based three-dimensional (3D) modeling technique. Overall disc deformation was determined using the changes of the space geometry between upper and lower endplates of each intervertebral segment (C3/4, C4/5, C5/6, and C6/7). Five points (anterior, center, posterior, left, and right) of each disc were analyzed to examine the disc deformation distributions. The data indicated that between the functional maximum flexion and extension of the neck, the anterior points of the discs experienced large changes of distraction/compression deformation and shear deformation. The higher level discs experienced higher ranges of disc deformation. No significant difference was found in deformation ranges at posterior points of all the discs. The data indicated that the range of disc deformation is disc level dependent and the anterior region experienced larger changes of deformation than the center and posterior regions, except for the C6/7 disc. The data obtained from this study could serve as baseline knowledge for the understanding of the cervical spine disc biomechanics and for investigation of the biomechanical etiology of disc diseases. These data could also provide insights for development of motion preservation surgeries for cervical spine.

Changes in Foraminal Area with Anterior Decompression versus Keyhole Foraminotomy in the Cervical Spine: A Cadaveric Investigation

2014 ◽  
Vol 14 (11) ◽  
pp. S164-S165
Author(s):  
Jeremi M. Leasure ◽  
Jacqueline Nguyen ◽  
Calvin Kuo ◽  
Bryant Chu ◽  
Christopher P. Ames ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Anterior Decompression ◽  
Keyhole Foraminotomy ◽  
Foraminal Area

scholarly journals Evaluation of Concordance between Degenerative Changes on Neck X-Ray and Symptomatic Cervical Disc Herniation

2020 ◽  
Vol 8 (2) ◽  
pp. 22
Author(s):  
Amir Abbas Ghasemi ◽  
Saber Ramezanpour
Keyword(s):  
Cervical Spine ◽  
Disc Herniation ◽  
Demographic Data ◽  
Degenerative Changes ◽  
Cervical Disc Herniation ◽  
Cervical Disc ◽  
Cross Sectional ◽  
Radiographic Findings ◽  
X Ray ◽  
Level Group

Objectives: Radiographic assessment of cervical spine can help find the etiology of neck symptoms, however association between these findings is debatable. The aim of this study was to investigate the association between degenerative changes of the cervical spine and symptomatic cervical disc herniation. Patients and Methods: This cross-sectional retrospective study included 160 patients who underwent anterior cervical discectomy and fusion between February 2012 and June 2017 for cervical disc herniation. Demographic data, patients’ symptoms and radiographic findings and indices were evaluated. The Chi-Square (X2) and one-way ANOVA were used to compare the observed data. Results: A total of 160 patients were studied. Among them, 83 (52%) were male and 77(48%) were female. The patients were classified into four groups on the basis of imaging findings: 89(55.6%) with degenerative changes and symptomatic disc herniation at the same level (group 1), 40(25%) with degenerative changes at a level adjacent to symptomatic level (group 2), 23(14.3%) with symptomatic herniation both at the degenerated level and at level immediately adjacent to it (group 3), and 8(5%) symptomatic herniation and degenerative changes at non-adjacent levels (group 4). There were no significant differences among the four groups from the viewpoint of gender, age, symptoms, smoking and sedentary life style. The study also showed no significant differences between groups with respect to Ishihara index, disc height and posterior osteophyte length. Conclusion: Degenerative changes visible on neck X-ray can be useful clues to the symptomatic disc herniation, but disc herniation may also develop at adjacent and non-adjacent levels.

Influence of Cervical Disc Degeneration after Posterior Surgical Techniques in Combined Flexion-Extension—A Nonlinear Analytical Study

2005 ◽  
Vol 127 (1) ◽  
pp. 186-192 ◽  
Author(s):  
Hong-Wan Ng ◽  
Ee-Chon Teo ◽  
Qinghang Zhang
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Cortical Bone ◽  
Rotational Motion ◽  
Surgical Techniques ◽  
Cervical Disc ◽  
Spinal Instability ◽  
Disk Degeneration ◽  
Flexion Extension ◽  
Rotational Motions

Laminectomy and facetectomy are surgical techniques used for decompression of the cervical spinal stenosis. Recent in vitro and finite element studies have shown significant cervical spinal instability after performing these surgical techniques. However, the influence of degenerated cervical disk on the biomechanical responses of the cervical spine after these surgical techniques remains unknown. Therefore, a three-dimensional nonlinear finite element model of the human cervical spine (C2–C7) was created. Two types of disk degeneration grades were simulated. For each grade of disk degeneration, the intact as well as the two surgically altered models simulating C5 laminectomy with or without C5–C6 total facetectomies were exercised under flexion and extension. Intersegmental rotational motions, internal disk annulus, cancellous and cortical bone stresses were obtained and compared to the normal intact model. Results showed that the cervical rotational motion decreases with progressive disk degeneration. Decreases in the rotational motion due to disk degeneration were accompanied by higher cancellous and cortical bone stress. The surgically altered model showed significant increases in the rotational motions after laminectomies and facetectomies when compared to the intact model. However, the percentage increases in the rotational motions after various surgical techniques were reduced with progressive disk degeneration.

scholarly journals Multi-Body Dynamic Analysis of Cervical Spine for Helicopter Pilots

2021 ◽  
Author(s):  
Hojjat Fathollahi
Keyword(s):  
Cervical Spine ◽  
Dynamic Model ◽  
Night Vision ◽  
Cervical Disc ◽  
Published Data ◽  
Lateral Bending ◽  
Flexion Extension ◽  
Helicopter Pilots ◽  
Multi Body ◽  
Body Dynamic

Helicopter pilots use helmets equipped with night vision goggle and counter weight. This increased load can lead to disc injury, so it is necessary to evaluate the load and moments applied to each cervical disc when pilot head is moving in different flight conditions. A 3D multi-body dynamic model of cervical spine is provided to investigate the effect of weight of the helmet in flexion, extension, lateral bending and axial rotation of the spine. The whole study was done in several steps: 1) to develop a non-linear dynamic model of spine. 2) to validate the model against the published data under flexion, extension, lateral bending and torsinal moments. 3) to solve three case studies to simulate a moving head in different direction. 4) to run the simulations again with consideration of adding a helmet into the model with different weight to find out the effects on the cervical discs loading. The results demonstrate that C2C3, C4C5 and C7T1 carry the highest loads depending on direction of imposed displacement on the head. Experts in the area of neck injury can study the results and locate the regions at risk of injury or they can feed this information into FEA model to get stress distribution in discs, bones or ligaments.

Cervical Disc Height During Dynamic In Vivo Flexion-Extension

2011 ◽  
Author(s):  
William J. Anderst ◽  
Thomas P. Lacek ◽  
William F. Donaldson ◽  
Joon Y. Lee ◽  
James D. Kang
Keyword(s):  
Cervical Spine ◽  
Cervical Disc ◽  
Dynamic Motion ◽  
System A ◽  
Spine Kinematics ◽  
Flexion Extension ◽  
The Us ◽  
Custom Software ◽  
Vertebral Kinematics

Cervical disc degeneration is a common and potentially debilitating disease. Over 100,000 surgical procedures are performed per year in the US to treat degenerative cervical spines1. However, the in vivo kinematics and arthrokinematics of the cervical spine have yet to be adequately characterized due to the inability to precisely track vertebral movement during dynamic motion. We have recently established the validity of a set of tools, including a biplane x-ray system, a model-based tracking technique and custom software, to precisely measure in vivo cervical spine kinematics and arthrokinematics with sub-millimeter accuracy2. Consequently, we can now begin to investigate the interdependent relationship between cervical vertebral kinematics and disc morphology and mechanical properties.

In vitro evaluation of a ball-and-socket cervical disc prosthesis with cranial geometric center

2009 ◽  
Vol 11 (5) ◽  
pp. 538-546 ◽  
Author(s):  
Cédric Barrey ◽  
Thomas Mosnier ◽  
Jérôme Jund ◽  
Gilles Perrin ◽  
Wafa Skalli
Keyword(s):  
Cervical Spine ◽  
Axial Rotation ◽  
Cervical Disc ◽  
Disc Prosthesis ◽  
Lateral Bending ◽  
Flexion Extension ◽  
Cervical Disc Prosthesis ◽  
Before And After ◽  
Left And Right

Object Few biomechanical in vitro studies have reported the effects of disc replacement on motion and kinematics of the cervical spine. The purpose of this study was to analyze motion through 3D load-displacement curves before and after implantation of a ball-and-socket cervical disc prosthesis with cranial geometric center; special focus was placed on coupled motion, which is a well-known aspect of normal cervical spine kinematics. Methods Six human cervical spines were studied. There were 3 male and 3 female cadaveric specimens (mean age at death 68.5 ± 5 years [range 54–74 years]). The specimens were evaluated sequentially in 2 different conditions: first they were tested intact; then the spinal specimens were tested after implantation of a ball-and-socket cervical disc prosthesis, the Discocerv, at the C5–6 level. Pure moment loading was applied in flexion/extension, left and right axial rotation, and left and right lateral bending. All tests were performed under load control with a 3D measurement system. Results No differences were found to be statistically significant after comparison of range of motion between intact and instrumented spines for all loading conditions. The mean range of motion for intact spines was 10.3° in flexion/extension, 5.6° in lateral bending, and 5.4° in axial rotation; that for instrumented spines was 10.4, 5.2, and 4.8°, respectively. No statistical difference was observed for the neutral zone nor stiffness between intact and instrumented spines. Finally, the coupled motions were also preserved during axial rotation and lateral bending, with no significant difference before and after implantation. Conclusions This study demonstrated that, under specific testing conditions, a ball-and-socket joint with cranial geometrical center can restore motion in the 3 planes after discectomy in the cervical spine while maintaining physiological coupled motions during axial rotation and lateral bending.

scholarly journals Patterns of Cervical Disc Degeneration: Analysis of Magnetic Resonance Imaging of Over 1000 Symptomatic Subjects

2017 ◽  
Vol 8 (3) ◽  
pp. 254-259 ◽  
Author(s):  
Akinobu Suzuki ◽  
Michael D. Daubs ◽  
Tetsuo Hayashi ◽  
Monchai Ruangchainikom ◽  
Chenjie Xiong ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Cervical Spine ◽  
Magnetic Resonance ◽  
Disc Degeneration ◽  
Large Population ◽  
Cross Sectional Study ◽  
Cervical Disc ◽  
Sectional Study ◽  
Resonance Imaging ◽  
Cross Sectional

Study Design: Cross-sectional study. Objectives: The aim of this study was to evaluate cervical disc degeneration on magnetic resonance imaging (MRI) in a large population of symptomatic patients and to provide baseline data on the pattern of degeneration in order to understand how the cervical spine ages. Methods: We performed a cross-sectional study of 1059 patients who underwent upright cervical MRI for neck pain with and without neurological symptoms. A total of 6354 cervical discs from C2/3 to C7/T1 were evaluated. Cervical disc degeneration was evaluated on T2-weighted MRI and graded into 4 categories (Grades 0-III). Positive degeneration was defined as greater than Grade II. The correlation between age and total grade of degeneration of each patient was evaluated, as well as the prevalence and pattern of degeneration. Results: The average number of degenerated disc levels and the total grade of cervical disc degeneration significantly increase with age. In the patient group with 1-level degeneration, C5/6 was the most common degenerated level followed by C4/5 and C6/7. In the group with 2-level degeneration, C5/6 & C6/7 was most common followed by C4/5 & C5/6 and C3/4 & C4/5. Skip level degeneration was significantly rarer than contiguous level degeneration, and C7/T1 and C2/3 were the most unlikely to degenerate in multilevel degeneration. Conclusion: Disc degeneration is most common in the middle cervical spine (C5/6) and progresses to contiguous levels, except for C7/T1 and C2/3. This pattern may play a role in adjacent-level disc degeneration associated with spinal fusion.

scholarly journals Cortical bone facet spacers for cervical spine decompression: effects on intervertebral kinetics and foraminal area

2016 ◽  
Vol 24 (1) ◽  
pp. 69-76 ◽  
Author(s):  
Christopher M. Maulucci ◽  
Charles A. Sansur ◽  
Vaneet Singh ◽  
Alexandra Cholewczynski ◽  
Snehal S. Shetye ◽  
...  
Keyword(s):  
Cervical Spine ◽  
Cortical Bone ◽  
Posterior Instrumentation ◽  
Principal Component ◽  
Biomechanical Study ◽  
Nerve Roots ◽  
En Bloc ◽  
Cross Sectional ◽  
Subaxial Cervical Spine ◽  
Foraminal Area

OBJECT Nerve root decompression to relieve pain and radiculopathy remains one of the main goals of fusion-promoting procedures in the subaxial cervical spine. The use of allograft facet spacers has been suggested as a potential alternative for performing foraminotomies to increase the space available for the cervical nerve roots while providing segmental stiffening. Therefore, the goal of this cadaveric biomechanical study was to determine the acute changes in kinetics and foraminal area after the insertion of cortical bone facet spacers into the subaxial cervical spine. METHODS Allograft spacers (2 mm in height) were placed bilaterally into cadaveric cervical spine specimens (C2-T1, age of donors 57.5 ± 9.5 years, n = 7) at 1 (C4–5) and 3 (C3–6) levels with and without laminectomies and posterior lateral mass screw fixation. Standard stereophotogrammetry under pure moment loading was used to assess spinal kinetics. In addition, the authors performed 3D principal component analysis of CT scans to determine changes in foraminal cross-sectional area (FCSA) available for the spinal nerve roots. RESULTS Generally, the introduction of 2-mm-height facet spacers to the cervical spine produced mild, statistically insignificant reductions in motion with particular exceptions at the levels of implantation. No significant adjacent-level motion effects in any bending plane were observed. The addition of the posterior instrumentation (PI) to the intact spines resulted in statistically significant reductions in motion at all cervical levels and bending planes. The same kinetic results were obtained when PI was added to spines that also had facet spacers at 3 levels and spines that had been destabilized by en bloc laminectomy. The addition of 2-mm facet spacers at C3–4, C4–5, and C5–6 did produce statistically significant increases in FCSA at those levels. CONCLUSIONS The addition of allograft cervical facet spacers should be considered a potential option to accomplish indirect foraminal decompression as measured in this cadaveric biomechanical study. However, 2-mm spacers without supplemental instrumentation do not provide significantly increased spinal segmental stability.

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